Various types of safety devices are provided to prevent an occupant seated in a vehicle or a machine from being catapulted out of the vehicle or the machine due to a collision between vehicles or a collision with other objects.
A seat belt is the representative safety device among the safety devices, and a lower abdomen and a chest of the occupant seated in the vehicle or the machine are stably fixed to the seat by using the seat belt.
A retractor, which serves to fix a user's body by pulling webbing with appropriate retracting force in a state in which the user fastens the seat belt and to prevent the retracted webbing from being extended again in a specific situation such as an accident, is widely applied.
The retractor may have various functions such as an automatic locking retractor function, a block out function, and an emergency locking retractor function.
The automatic locking retractor (ALR) function refers to a function in which when the user extends an overall length of the webbing, an automatic locking function is performed such that the webbing is not extended any further and the webbing may just be retracted, for example, like a method that mounts an infant seat into a vehicle or mount a device into a seat, and then restricts the infant seat or the device.
The block out (B/O) function refers to a function that detects a gradient of a vehicle body, and prevents an operation of a tilt sensor, when the vehicle body is tilted at a predetermined angle or greater, by operating a locking mechanism in order to forcedly release a function of inhibiting the webbing from being extended. The block out function refers to a function for preventing a situation in which the seat cannot return back to an original state as the seat mounted with the retractor is folded and tilted at a predetermined angle or greater and the locking mechanism is operated.
The emergency locking retractor (ELR) function refers to a function in which a locking mechanism for the retractor prevents the webbing from being released in the case of emergency such as a case in which impact is applied to the vehicle or a rollover accident occurs.
However, because constituent elements capable of implementing the automatic locking retractor function, the block out function, and the emergency locking retractor function are different from one another, it is very difficult for a single retractor to implement all of these functions.
However, with the technology development, models, which implement all of these functions by using a single retractor, have been developed and used, but the models in the related art have problems in that noise of a ball member embedded in the locking mechanism are not removed, and structures of the models are very complicated because the number of components of the retractor is increased.
Recently, as regulations regarding safety evaluation become stricter, there is a need for development of technologies for adjusting severity of injury according to the occupants by classifying the occupants into adult persons, old or weak persons, female persons, and children and adjusting an operation of deploying an airbag. To this end, it is necessary to essentially develop a system for identifying occupants by specifying the occupants' bodies.